The Advocacy Coalition Framework (ACF), developed by Paul Sabatier, is generally considered one of the most promising theories of the policy process (see, for instance, Parsons, 1995; Eberg, 1997; Schlager and Blomquist, 1996; Grin and Hoppe, 1997). The framework considers policy change as the result of learning processes within and between advocacy coalitions. However, in explaining policy change, the ACF focuses almost exclusively on the structure, content, stability, and evolution of the policy belief systems of advocacy coalitions. There is no attempt to account for how actors with certain policy belief systems develop and maintain these advocacy coalitions.

From the literature on interorganizational relations and policy networks, we know that the extent and structure of interdependencies between actors are important determinants of the behavior of the actors in interorganizational relations. Differences in interdependencies are supposed to lead to different types of interorganizational arrangements.

In this article, a hypothesis is developed that explains the development and maintenance of advocacy coalitions by looking at both the interdependencies and the policy belief systems of the actors. The importance of this approach is demonstrated by applying it to the debate on oil and gas leasing in the outer continental shelf of the United States. It turns out that the attention for interdependency contributes significantly to the possibilities of explaining the behavior of single actors and advocacy coalitions